We have published in Biological Psychology a report of seasonal effects on the amplitude of cognitive ERP (Event-Related brain Potentials) components. In preparation at this time are reports of the effects of clonidine (a norepinephrine blocker) on ERPs in normal subjects, as well as a comparison among normal controls and two groups of patients with seizure disorders. The latter study indicated that ERPs in patients with temporal lobe seizures resemble in most respects those seen in normal control subjects; in contrast, ERPs in patients with absence epilepsy show reduced amplitudes of cognitive components, especially P300 and slow wave. The differences were seen primarily in the processing of auditory signals. We are hoping to reactivate this project, in conjunction with colleagues at the Uniformed Services University of the Health Sciences. A manuscript describing the effects of closed head injuries on ERPs in attention-demanding tasks has been published by the journal Psychophysiology. The findings indicate that changes in the N200 component, concerned with identification and classification of stimuli, is altered in these patients, particularly in the auditory modality. These are presumably permanent changes in information processing, as trhe patients were on the average seven years post-injury.